Prothrombin Time Testing: Principles, Methodology, Clinical Interpretation, and Quality Assurance in Hemostasis Laboratories
Abstract
Background: Prothrombin time (PT) is a critical coagulation assay widely used to assess the extrinsic and common pathways of hemostasis. It plays a pivotal role in monitoring anticoagulant therapy, evaluating bleeding risk, and diagnosing systemic disorders such as liver disease and disseminated intravascular coagulation.
Aim: This review aims to provide a comprehensive overview of PT testing, including its principles, methodology, clinical interpretation, and quality assurance practices in modern hemostasis laboratories.
Methods: The article synthesizes current evidence and best practices regarding PT assay performance, specimen collection, endpoint detection technologies, and quality control measures. It also examines preanalytical, analytical, and postanalytical factors influencing test reliability.
Results: PT testing has evolved from manual tilt-tube techniques to automated optical and mechanical detection systems, improving precision and scalability. The introduction of the International Normalized Ratio (INR) standardized reporting across laboratories, enhancing safety in anticoagulation management. Point-of-care (POC) devices have expanded access to rapid testing, though limitations persist in critically ill patients. Quality assurance, including internal QC, reagent lot verification, and external proficiency testing, remains essential to ensure accuracy.
Conclusion: PT/INR testing is indispensable for clinical decision-making, but its reliability depends on rigorous preanalytical control, method-aware interpretation, and adherence to quality standards. Technological advances and decentralized testing models offer convenience but require careful oversight to maintain patient safety.
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References
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Copyright (c) 2025 Mohammed Ibrahim Mohsen Gomer, Abdullah Essa Magbool Oraybi, Khalid Hamoud Najea Somaily, Ahlam Mohammed Ahmed Arishi, Essa Ali Ali Oraybi, Abdullah Zain Abdullah Abbas, Muteeb Mohamed Alasiri, Badr Amer Alhrbi, Samar Ahmad Breagesh, Khlood Abdu Ali Dagreery
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